nfsd: populate sin6_scope_id on callback address with scopeid from rq_addr on SETCLIENTID call

When a SETCLIENTID call comes in, one of the args given is the svc_rqst.
This struct contains an rq_addr field which holds the address that sent
the call. If this is an IPv6 address, then we can use the sin6_scope_id
field in this address to populate the sin6_scope_id field in the
callback address.

AFAICT, the rq_addr.sin6_scope_id is non-zero if and only if the client
mounted the server's link-local address.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

2 files changed, 20 insertions, 2 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 9ec0ca1ef4ea..d2a052480908 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -898,7 +898,7 @@ find_unconfirmed_client_by_str(const char *dname, unsigned int hashval,
 }
 
 static void
-gen_callback(struct nfs4_client *clp, struct nfsd4_setclientid *se)
+gen_callback(struct nfs4_client *clp, struct nfsd4_setclientid *se, u32 scopeid)
 {
         struct nfs4_cb_conn *cb = &clp->cl_cb_conn;
         unsigned short expected_family;
@@ -921,6 +921,9 @@ gen_callback(struct nfs4_client *clp, struct nfsd4_setclientid *se)
         if (!cb->cb_addrlen || cb->cb_addr.ss_family != expected_family)
                 goto out_err;
 
+        if (cb->cb_addr.ss_family == AF_INET6)
+                ((struct sockaddr_in6 *) &cb->cb_addr)->sin6_scope_id = scopeid;
+
         cb->cb_minorversion = 0;
         cb->cb_prog = se->se_callback_prog;
         cb->cb_ident = se->se_callback_ident;
@@ -1621,7 +1624,7 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
         }
         copy_cred(&new->cl_cred, &rqstp->rq_cred);
         gen_confirm(new);
-        gen_callback(new, setclid);
+        gen_callback(new, setclid, rpc_get_scope_id(sa));
         add_to_unconfirmed(new, strhashval);
         setclid->se_clientid.cl_boot = new->cl_clientid.cl_boot;
         setclid->se_clientid.cl_id = new->cl_clientid.cl_id;
diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index 044f531aee70..3d025588e56e 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -286,5 +286,20 @@ static inline bool rpc_copy_addr(struct sockaddr *dst,
         return false;
 }
 
+/**
+ * rpc_get_scope_id - return scopeid for a given sockaddr
+ * @sa: sockaddr to get scopeid from
+ *
+ * Returns the value of the sin6_scope_id for AF_INET6 addrs, or 0 if
+ * not an AF_INET6 address.
+ */
+static inline u32 rpc_get_scope_id(const struct sockaddr *sa)
+{
+        if (sa->sa_family != AF_INET6)
+                return 0;
+
+        return ((struct sockaddr_in6 *) sa)->sin6_scope_id;
+}
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_SUNRPC_CLNT_H */